If you keep your database in gmail or don’t really have a database other than customers that you talk to through email, you can export your Gmail contacts*. To do this, follow these steps:
- Sign in to Gmail.
- At the top left, click Mail > Contacts.
- Click More > Export...
- Choose whether to export all contacts or only one group.
- Select Google CSV format
- Click Export.
- You may now need to choose where to save the file, or it may automatically go to your downloads folder.
- Head here and upload the database which should be called something ending with .csv
*you should have permission from these guys to add them to a marketing database.